WO2023188749A1

WO2023188749A1 - Combustor and gas turbine

Info

Publication number: WO2023188749A1
Application number: PCT/JP2023/002252
Authority: WO
Inventors: 信一福場; 志張; 圭祐三浦; 朋川上; 喜敏藤本; 拓江川; 健太谷口
Original assignee: 三菱パワー株式会社; 三菱重工業株式会社
Priority date: 2022-03-30
Filing date: 2023-01-25
Publication date: 2023-10-05

Abstract

This combustor comprises: a combustor plate that has a mixing tube which extends so as to penetrate the combustor plate upstream end face and downstream end face perpendicular to the combustor axis and into which air is introduced from the upstream end face side; a first fuel injection part that is capable of injecting a first fuel along the center axis of the mixing tube on the inner side of the mixing tube; and a second fuel injection part that is capable of injecting a second fuel within the mixing tube radially outward of the center axis of the mixing tube.

Description

Combustor and gas turbine

TECHNICAL FIELD This disclosure relates to combustors and gas turbines.
This application claims priority to Japanese Patent Application No. 2022-56200 filed in Japan on March 30, 2022, the contents of which are incorporated herein.

For example, Patent Document 1 discloses a cluster combustor as an example of a combustor used in a gas turbine.

The cluster combustor has a plurality of mixing tubes that are arranged in parallel with each other and into which air is introduced, and a fuel nozzle that injects fuel from the tips inserted into these mixing tubes. The fuel nozzle injects fuel along the central axis of the mixing tube.
As fuel is injected from the fuel nozzle, a mixed gas of air and fuel flows through the mixing pipe and is ejected downstream. At this time, by igniting the mixed gas, a plurality of small-scale flames are formed at the outlet of each mixing tube.

US Patent Application Publication No. 2013/0067926

In the combustor as described above, it is necessary to suppress an increase in the fuel concentration on the inner wall surface of the mixing tube in order to suppress flashback in which the flame flows back along the wall surface within the mixing tube. This tendency is particularly noticeable when relatively easily flammable fuel is used.
On the other hand, especially when a relatively hard-to-flammable fuel is used, if the fuel concentration on the inner wall surface is low, there is a risk of misfire, and stable combustion may not be possible.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a combustor and a gas turbine that can avoid misfires while suppressing flashback.

In order to solve the above problems, a combustor according to the present disclosure has a mixing tube that extends through an upstream end surface and a downstream end surface that are perpendicular to the combustor axis, and into which air is introduced from the upstream end surface side. a first fuel injector capable of injecting a first fuel along the central axis of the mixing tube inside the mixing tube; and a second fuel injection section capable of injecting two fuels.

A gas turbine according to the present disclosure includes: a compressor that generates air; the above-mentioned combustor that generates combustion gas by combusting a premixed gas generated by mixing fuel into the air compressed by the compressor; A turbine driven by combustion gas.

According to the combustor and gas turbine of the present disclosure, misfire can be avoided while suppressing flashback.

1 is a schematic diagram showing a schematic configuration of a gas turbine according to a first embodiment of the present disclosure. FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a combustor according to a first embodiment of the present disclosure. FIG. 2 is a vertical cross-sectional view of a main part of a combustor plate of a combustor according to a first embodiment of the present disclosure. FIG. 3 is a perspective view of the inside of the mixing tube of the combustor plate of the combustor according to the first embodiment of the present disclosure. FIG. 7 is a vertical cross-sectional view of a main part of a combustor plate of a combustor according to a second embodiment of the present disclosure. FIG. 7 is a vertical cross-sectional view of a main part of a combustor plate of a combustor according to a third embodiment of the present disclosure, also showing the cross-sectional shape of a strut.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4. As shown in FIG. 1, the gas turbine 1 according to the present embodiment includes a compressor 2 that compresses air A, a combustor 3 that generates combustion gas C, and a turbine 4 that is driven by the combustion gas C. have.
A plurality of combustors 3 are provided around the rotating shaft of the gas turbine 1 at intervals in the circumferential direction. The combustor 3 mixes fuel with the air A compressed by the compressor 2 and combusts the mixture to generate high-temperature, high-pressure combustion gas C.

(combustor)
The configuration of the combustor 3 will be described below with reference to FIGS. 2 to 4.
The combustor 3 includes an outer cylinder 10, an end cover 11, an inner cylinder 15, a support part 17, a combustor plate 20, a first fuel injection part 40, and a second fuel injection part 70.

(outer cylinder)
The outer cylinder 10 has a cylindrical shape centered on a combustor axis O1 (hereinafter simply referred to as axis O1), which is the center of the combustor 3.

(end cover)
The end cover 11 has a disc shape that closes one end (the left side in FIG. 2) of the outer cylinder 10 in the direction of the axis O1. An end portion of the outer cylinder 10 on one side in the direction of the axis O1 is in contact with the end cover 11.

(inner cylinder)
The inner cylinder 15 is arranged coaxially inside the outer cylinder 10. The inner cylinder 15 has a cylindrical shape extending in the direction of the axis O1 inside the outer cylinder 10. An end portion of the inner cylinder 15 on one side in the direction of the axis O1 is spaced apart from the end cover 11 in the direction of the axis O1. The outer diameter of the inner cylinder 15 is smaller than the inner diameter of the outer cylinder 10. Thereby, an annular flow path is formed between the outer peripheral surface of the inner cylinder 15 and the inner peripheral surface of the outer cylinder 10. Air A compressed by the compressor 2 flows through the flow path from the other side in the axis O1 direction (the right side in FIG. 2) toward the one side in the axis O1 direction.

(Support part)
The support portions 17 are members extending in the direction of the axis O1, and a plurality of support portions 17 are provided at intervals in the circumferential direction. An end portion of the support portion 17 on one side in the axis O1 direction is fixed to a surface of the end plate facing the other side in the axis O1 direction on the inner peripheral side of the outer cylinder 10. The air A that has flown between the outer cylinder 10 and the inner cylinder 15 on one side in the direction of the axis O1 reverses its flow direction to the other side in the direction of the axis O1 when passing between the mutually adjacent support parts 17.

(combustor plate)
The combustor plate 20 has a disk shape centered on the axis O1. The combustor plate 20 is provided so as to be coaxially fitted inside the inner cylinder 15. Combustor plate 20 has an upstream end surface 21 and a downstream end surface 22.

(Upstream end face)
The upstream end surface 21 is an end surface of the combustor plate 20 facing one side in the direction of the axis O1, and has a planar shape orthogonal to the axis O1. The upstream end surface 21 is arranged at the same position in the axis O1 direction as the end surface of the inner cylinder 15 on one side in the axis O1 direction.

(Downstream end face)
The downstream end surface 22 is an end surface of the combustor plate 20 facing the other side in the direction of the axis O1, and has a planar shape orthogonal to the axis O1. The downstream end surface 22 is located on one side in the direction of the axis O1 than the end surface of the inner cylinder 15 on the other side in the direction of the axis O1. As a result, a space is defined by the inner peripheral surface of the inner cylinder 15 and the downstream end surface 22 of the combustor plate 20. This space is the combustion space of the combustor 3.

(mixing tube)
The mixing tube 30 is a tube extending in the direction of the axis O1, and air A flows into it from the upstream side (one side in the direction of the axis O1, the left side in FIG. 2). The mixing pipe 30 of this embodiment is formed as a hole extending in the direction of the axis O1 so as to pass through the upstream end surface 21 and the downstream end surface 22 of the combustor plate 20. The mixing tubes 30 extend linearly in the direction of the axis O1, and a plurality of mixing tubes 30 are arranged in parallel at intervals in a direction perpendicular to the axis O1. The opening on the upstream end surface 21 side of the mixing tube 30 is an upstream inlet opening 31 into which air A flows. The opening on the downstream end surface 22 side of the mixing tube 30 is a downstream outlet opening 32 through which a premixed gas M of air A and fuel is ejected. The cross section of the flow path of the mixing tube 30 has a circular shape centered on the central axis O2 of the mixing tube 30.

Specifically, as shown in FIG. 3, the inner wall surface 33, which is the inner circumferential surface of the mixing tube 30, is composed of three parts: an upstream wall surface 33a, a reduced diameter wall surface 33b, and a downstream wall surface 33c.

The upstream wall surface 33a is the most upstream portion of the inner wall surface 33 of the mixing tube 30. The upstream wall surface 33a has a circular cross-sectional shape perpendicular to the axis O1 at any central axis O2 position. The upstream wall surface 33a has a uniform inner diameter along the central axis O2 direction. The upstream end of the upstream wall surface 33a is the inlet opening 31.

The reduced diameter wall surface 33b is connected to the downstream end of the upstream wall surface 33a. The diameter-reducing wall surface 33b has a tapered shape whose diameter gradually decreases toward the downstream side. The inner diameter of the upstream end of the reduced diameter wall surface 33b is the same as the inner diameter of the downstream end of the upstream wall surface 33a. Thereby, the upstream wall surface 33a and the reduced diameter wall surface 33b are smoothly connected to each other without forming a step at the boundary. The diameter-reduced wall surface 33b may have a conical shape or may have a convex curved shape that is convex toward the inner wall surface 33 of the mixing tube 30. The diameter-reduced wall surface 33b has a circular cross-sectional shape perpendicular to the center axis O2 at any position of the center axis O2.

The downstream wall surface 33c is connected to the downstream end of the reduced diameter wall surface 33b. The downstream wall surface 33c has a circular cross-sectional shape perpendicular to the axis O1 at any central axis O2 position. The inner diameter of the upstream end of the downstream wall surface 33c is the same as the inner diameter of the downstream end of the reduced diameter wall surface 33b. Thereby, the diameter-reduced wall surface 33b and the downstream wall surface 33c are smoothly connected to each other without forming a step at their boundary. The downstream wall surface 33c has a uniform inner diameter along the central axis O2 direction. The inner diameter of the downstream wall surface 33c is one size smaller than that of the upstream wall surface 33a. The downstream end of the downstream wall surface 33c is the outlet opening 32.

(First plenum, second plenum)
As shown in FIGS. 2 and 3, a first plenum 35 and a second plenum 36 are formed inside the combustor plate 20 so as to avoid the mixing pipe 30. The first plenum 35 and the second plenum 36 are separated from the flow path within the mixing tube 30 via a wall that forms the inner wall surface 33 of the mixing tube 30. The first plenum 35 and the second plenum 36 are not in communication with each other. That is, the first plenum 35 and the second plenum 36 are defined in the combustor plate 20 independently from each other so as not to interfere with each other.

The first fuel F1 is supplied into the first plenum 35 via a first fuel supply system 38 passed through a connecting member 37 that connects the outer cylinder 10 and the inner cylinder 15, for example. As a result, the space within the first plenum 35 is filled with the first fuel F1.
A second fuel F2 is supplied into the second plenum 36, for example, via a second fuel supply system 39 passed through the support portion 17. As a result, the space within the second plenum 36 is filled with the second fuel F2.
Note that the first fuel supply system 38 may be passed through the support portion 17, and the second fuel supply system 39 may be passed through the connection member 37. In addition, the first fuel supply system 38 and the second fuel supply system 39 may be provided at arbitrary locations.

Here, in this embodiment, the first fuel F1 is a fuel that is more flammable than the second fuel F2. That is, the first fuel F1 has higher combustibility than the second fuel F2. For example, hydrogen is used as the first fuel F1. For example, natural gas is used as the second fuel F2. Hydrogen is a more flammable fuel than natural gas.

(First fuel injection part)
The first fuel injection section 40 injects the first fuel F1 into the mixing tube 30 along the central axis O2 of the mixing tube 30. The first fuel injection section 40 has a fuel nozzle 41, a strut 50, and a fuel introduction section 60.

The fuel nozzle 41 is a long member disposed within the mixing tube 30 and extending in the direction of the central axis O2 of the mixing tube 30. The fuel nozzle 41 is provided coaxially with the inner wall surface 33 of the mixing tube 30 and spaced apart from the inner wall surface 33 in the radial direction of the mixing tube 30 .

The fuel nozzle 41 has a cylindrical shape with a bottom that is closed on the upstream side and open on the downstream side. The upstream end of the fuel nozzle 41 has a tapered shape that decreases in diameter toward the upstream side. That is, the upstream end of the fuel nozzle 41 has a tapered shape toward the upstream side. The outer circumferential surface of the fuel nozzle 41, which is connected to the downstream end of the upstream end of the fuel nozzle 41, has a cylindrical shape extending in the direction of the central axis O2 and centered on the central axis O2. The outer circumferential surface of the fuel nozzle 41 may have a tapered shape that decreases in diameter toward the downstream side, that is, may have a tapered shape toward the downstream side.

In this embodiment, the upstream end of the fuel nozzle 41 is located at the location where the upstream wall surface 33a is formed on the inner wall surface 33 of the mixing pipe 30. The downstream end of the fuel nozzle 41 is located at the boundary between the diameter-reduced wall surface 33b and the downstream wall surface 33c on the inner wall surface 33 of the mixing tube 30.

The cross-sectional shape of the fuel nozzle 41 perpendicular to the central axis O2 has a circular shape centered on the central axis O2 at any position in the direction of the central axis O2. Thereby, an annular flow path centered on the central axis O2 is formed between the fuel nozzle 41 and the inner wall surface 33.

The upstream portion of the space inside the fuel nozzle 41 is a cavity 42 that opens into the mixing pipe 30 at the downstream end of the fuel nozzle 41. The opening of the cavity 42 is the tip opening 45 of the fuel nozzle 41. The tip opening 45 has a circular shape centered on the central axis O2.

(Strut)
A plurality of struts 50 are provided in the flow path between the inner wall surface 33 of the mixing pipe 30 and the fuel nozzle 41 at intervals in the circumferential direction. The strut 50 has the role of holding the fuel nozzle 41 within the mixing tube 30. The strut 50 has its radially outer end connected to the inner wall surface 33 of the mixing tube 30 with respect to the central axis O2, and the strut 50 with its radially inner end connected to the fuel nozzle 41.

The strut 50 has an airfoil-shaped cross section perpendicular to the radial direction of the central axis O2. That is, the strut 50 has a shape in which an airfoil is extended in the radial direction of the central axis O2. In other words, the strut 50 has a blade shape with the radial direction of the central axis O2 being the blade height direction.

The upstream end of the strut 50 is a front edge 51 that extends in the radial direction. The leading edge 51 extends radially inward of the central axis O2 toward the downstream side. Thereby, the upstream end of the leading edge 51 is connected to the inner wall surface 33 of the mixing pipe 30, and the downstream end of the leading edge 51 is connected to the fuel nozzle 41.

The downstream end of the strut 50 is a radially extending trailing edge 52 . The rear edge 52 extends in a radial direction of the central axis O2.
In accordance with the shape of the leading edge 51, the shape of the airfoil in a cross section perpendicular to the radial direction of the central axis O2 of the strut 50 becomes larger toward the outside in the radial direction. The strut 50 has a shape in which airfoils gradually become smaller from the outside in the radial direction to the inside in the radial direction of the central axis O2.

A pair of surfaces facing in the circumferential direction of the central axis O2 connecting the leading edge 51 and the trailing edge 52 of the strut 50 are blade surfaces 53. The pair of blade surfaces 53 are in contact with each other at the leading edge 51, and are gradually separated in the circumferential direction of the center axis O2 as they go downstream, and then gradually spaced apart in the circumferential direction of the center axis O2 as they go further downstream. They are adjacent to each other and connected to each other at trailing edges 52.
In this embodiment, such struts 50 are provided at equal intervals in the circumferential direction.

(Fuel introduction part)
The fuel introduction section 60 introduces the first fuel F1 into the fuel nozzle 41. The fuel introduction part 60 passes through the wall separating the inner wall surface 33 of the mixing tube 30 of the combustor plate 20 and the cavity 42 and the inside of the strut 50, and connects the first plenum 35 and the cavity 42 in the mixing tube 30. It communicates with The fuel introduction part 60 is a hole extending in the radial direction of the central axis O2 of the mixing tube 30, and its radially outer end of the central axis O2 is connected to the first plenum 35. The inner end in the direction is connected to the cavity 42 . A plurality of fuel introduction sections 60 may be provided corresponding to the plurality of struts 50, or may be provided only on some of the struts 50 among the plurality of struts 50.

(Second fuel injection part)
The second fuel injection section 70 supplies the second fuel F2 into the mixing tube 30 at a location radially outward from the central axis O2 of the mixing tube 30.
The second fuel injection section 70 of this embodiment has a wall hole 71 that can inject the second fuel F2 into the mixing tube 30 from the inner wall surface 33 of the mixing tube 30. The wall hole 71 is a hole extending linearly in the radial direction of the central axis O2, and has an end portion radially inside the central axis O2 that opens into the inner wall surface 33 of the inner wall surface 33, and a radially inner end of the central axis O2. The outer end opens into the second plenum 36 . Thereby, the wall hole 71 allows the flow path in the mixing tube 30 and the second plenum 36 to communicate with each other.

The wall hole 71 extends radially inward from the second plenum 36 toward the downstream side. That is, the wall hole 71 is formed so as to be inclined from the radial direction of the mixing tube 30 and the central axis O2. The angle of inclination of the wall hole 71 with respect to the central axis O2 is set to, for example, 30 to 80 degrees, preferably 40 to 70 degrees, and more preferably 45 degrees to 65 degrees.

A plurality of second fuel injection parts 70 may be formed spaced apart in the circumferential direction of the central axis O2, or only one second fuel injection part 70 may be formed.
The position of the second fuel injection section 70 in the direction of the central axis O2 is on the upstream side of the first fuel injection section 40. That is, the opening of the second fuel injection section 70 into the inner wall surface 33 of the mixing tube 30 is located upstream of the tip opening 45 of the fuel nozzle 41 of the first fuel injection section 40 .
In this embodiment, the opening point of the second fuel injection part 70 to the inner wall surface 33 of the mixing tube 30 is on the upstream wall surface 33a of the inner wall surface 33 of the mixing tube 30, and is closer to the upstream end of the strut 50. is also formed further upstream.

(action/effect)
Next, the operation, effects, and effects of the combustor 3 according to this embodiment will be explained.
As shown in FIG. 3, during operation of the gas turbine 1, air A enters into each mixing tube 30 of the combustor plate 20 from the upstream side, and air A flows through the mixing tube 30 toward the downstream side. In this state, when the first fuel F1 is injected into the mixing tube 30 by the first fuel injection section 40 or the second fuel F2 is injected into the mixing tube 30 by the second fuel injection section 70, the mixing tube 30 A premixed gas M is generated by mixing air A and fuel within. The premixed gas M is injected from the outlet opening 32 of the mixing tube 30 at the downstream end face 22 of the combustor plate 20 and ignited. As a result, the premixed gas M is combusted to generate a combustion gas C, and the combustion gas C is sent to the turbine 4, so that the turbine 4 is rotationally driven.

Here, when operating the gas turbine 1, there are cases in which only the first fuel F1, which is a relatively easily flammable fuel, is input into the combustor 3, and cases where only the second fuel F2, which is a relatively hard to combustible fuel, is input into the combustor 3. It may be thrown in. That is, the type of fuel may be switched depending on the operation of the gas turbine 1.

In this embodiment, the first fuel F1, which is a more flammable fuel, is supplied into the mixing pipe 30 via the first fuel injection section 40. That is, the fuel introduced into the cavity 42 of the fuel nozzle 41 from the first fuel F1 plenum via the fuel introduction part 60 is supplied into the mixing tube 30 via the tip opening 45. Since the tip opening 45 of the fuel nozzle 41 is arranged along the central axis O2 of the mixing tube 30, the first fuel F1 ejected from the tip opening 45 flows inside the mixing tube 30 along the central axis O2. circulate.

Therefore, the first fuel F1 is prevented from diffusing radially outward within the mixing tube 30, and the first fuel F1 is concentrated in the center of the mixing tube 30. That is, the fuel concentration distribution within the mixing tube 30 is higher on the radially inner side and lower on the radially outer side. Therefore, the fuel concentration near the inner wall surface 33 of the mixing tube 30 can be suppressed, thereby avoiding the occurrence of flashback in which the flame formed on the downstream end surface 22 flows backward along the inner wall surface 33 of the mixing tube 30. becomes possible. In particular, if the fuel is of a type that is easily flammable, flashback is likely to occur, but by injecting the first fuel F1 along the central axis O2 as in this embodiment, even in such a case, The occurrence of flashback can be appropriately avoided.

On the other hand, when injecting the second fuel F2, which is a relatively hard-to-flammable fuel, if it is injected along the central axis O2 of the mixing tube 30 like the first fuel F1, the risk of misfire will increase. That is, in the outlet opening 32 of the mixing tube 30, the outer edge of the opening becomes the starting point of flame stabilization. Therefore, if the hard-to-flammable fuel gathers in the center of the mixing tube 30, the starting point of flame holding in an area with high fuel concentration moves away from the fuel, making it impossible to hold a stable flame and causing a misfire. there is a possibility.

On the other hand, in this embodiment, when the second fuel F2, which is more difficult to burn, is injected, it is not ejected along the central axis O2 of the mixing tube 30, but at a point spaced apart in the radial direction from the central axis O2. erupts from. That is, the second fuel F2 is injected into the mixing tube 30 from the inner wall surface 33 of the mixing tube 30 by the second fuel injection section 70. Therefore, an extreme drop in fuel concentration near the wall surface of the mixing tube 30 can be avoided.

More specifically, by injecting the second fuel F2 from the inner wall surface 33 of the mixing tube 30 by the second fuel injection section 70, the fuel concentration on the inner wall surface 33 can be increased. Therefore, the fuel concentration near the inner wall surface 33 also increases near the outlet of the mixing tube 30, and the combustion rate at the outer edge of the outlet opening 32 of the mixing tube 30, which is the starting point of flame stabilization, can be increased. As a result, the flame can be continuously stabilized.

From the above, even when using fuels with different combustibility, it is possible to perform stable combustion while suppressing flashback.

In addition, when operating the combustor 3 with the second fuel F2, it is also possible to separately provide a combustor nozzle for flame stabilization with a high fuel concentration in order to ensure flame stabilization. However, in this case, there is a possibility that the temperature of the flame locally increases and the amount of NOx generated increases.
By adopting the configuration of this embodiment, flame stability can be ensured without providing a separate combustor nozzle, so it is possible to suppress the generation of NOx.

Here, in this embodiment, the second fuel injection section 70 is arranged on the upstream side within the mixing pipe 30, and the first fuel injection section 40 is arranged on the downstream side within the mixing pipe 30. Thereby, the flow path of the second fuel F2 from being injected to reaching the outlet opening 32 becomes sufficiently long. Therefore, the second fuel F2 can be sufficiently diffused and spread over the entire area in the cross section of the flow path of the mixing tube 30. As a result, the fuel concentration near the inner wall surface 33 of the mixing tube 30 can be ensured, and the occurrence of misfire can be avoided and stable flame holding can be performed.

On the other hand, the flow path from where the first fuel F1 is injected from the first fuel injection unit 40 to the outlet of the mixing pipe 30 becomes shorter. Therefore, since the straightness of the first fuel F1 can be ensured, it is possible to prevent the first fuel F1 from diffusing and reaching the inner wall surface 33 of the mixing pipe 30. As a result, the occurrence of flashback can be suppressed.

Furthermore, since the struts 50 have an airfoil shape, the air A within the mixing tube 30 can be smoothly circulated. Therefore, an increase in pressure loss can be suppressed.
Furthermore, in this embodiment, since the second fuel injection section 70 is provided on the upstream side of the strut 50, the ejected second fuel F2 also flows smoothly along the airfoil of the strut 50. Therefore, it is also possible to suppress an increase in pressure loss due to the generation of unintended vortices due to the jet flow of the second fuel F2. It is also possible to suppress imbalances in fuel distribution, such as local increases in fuel concentration.

Further, since a part of the mixing tube 30 is made into a diameter-reduced wall surface 33b and a constricted flow path is formed, the flow velocity within the mixing tube 30 can be increased. Thereby, it is possible to avoid unintentional flame holding due to unintentional accumulation of fuel in the mixing tube 30.

[Second embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. 5. In the second embodiment, the same components as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.
In the second embodiment, the configuration of the second fuel injection section 70 is different from the first embodiment. That is, the second fuel injection section 70 has a surface hole 72 through which the second fuel F2 is injected from the wing surface 53, which is the surface of the strut 50.

The surface hole 72 opens at the radially inner end of the mixing tube 30 into the blade surface 53 of the strut 50. A radially outer end of the surface hole 72 opens into the second plenum 36 . Thereby, the surface hole 72 communicates the inside of the mixing pipe 30 and the second plenum 36 via the blade surface 53 of the strut 50. The surface hole 72 may be formed in each of the pair of wing surfaces 53 of the strut 50, or may be formed in only one of the pair of wing surfaces 53. Furthermore, the surface holes 72 may be formed in each of the plurality of struts 50, or may be formed in only some of the struts 50.

With this configuration, the second fuel F2 can be injected into the mixing pipe 30 at a position radially outward from the central axis O2, similarly to the first embodiment. Therefore, compared to the case where the second fuel F2 is ejected along the central axis O2, the fuel concentration near the inner wall surface 33 of the mixing tube 30 can be increased, and flame stability can be ensured.

Furthermore, by ejecting the second fuel F2 into the flow of the air A that smoothly flows through the blade surface 53, it is possible to suppress the inadvertent generation of vortices due to the jet of the second fuel F2. Therefore, it is possible to suppress an increase in pressure loss within the mixing tube 30, and to avoid uneven fuel distribution.
On the other hand, since the second fuel F2 can be appropriately mixed with the air A flowing through the wing surface 53, the mixing of the air A and the second fuel F2 can be promoted, and NOx can be reduced. can.

[Third embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In the third embodiment, the same reference numerals are given to the same components as in the first embodiment, and detailed description thereof will be omitted.
In the third embodiment, the shape of the mixing tube 30 is different from the first embodiment.

The diameter-reduced wall surface 33b of the mixing tube 30 in the third embodiment is formed over a wider range than in the first embodiment. The upstream end of the reduced diameter wall surface 33b is located at the same position in the central axis O2 direction as the upstream end of the strut 50. As in the first embodiment, the downstream end of the reduced diameter wall surface 33b is located at the same position in the central axis O2 direction as the tip opening 45 of the fuel nozzle 41 of the first fuel injection section 40. The diameter-reducing wall surface 33b has a tapered shape that gradually reduces in diameter from the upstream end to the downstream end.

As described above, in this embodiment, the diameter-reduced wall surface 33b of the mixing tube 30 is provided at the position where the strut 50 is formed. Thereby, the cross-sectional area of the flow path of the mixing tube 30 can be configured to match the change in the shape of the strut 50. Therefore, it is possible to avoid the occurrence of a low speed region within the mixing tube 30, and it is possible to prevent flame holding from occurring inadvertently within the mixing tube 30.

(Other embodiments)
Although the embodiments of the present invention have been described above, the present invention is not limited thereto, and can be modified as appropriate without departing from the technical idea of the invention.

For example, in the embodiment, an example has been described in which hydrogen is used as the first fuel F1 and natural gas is used as the second fuel F2, but the present invention is not limited to this. Various fuels can be employed as the first fuel F1 and the second fuel F2.
Alternatively, at least one of the first fuel F1 and the second fuel F2 may be a mixed fuel of hydrogen and natural gas. In this case as well, the combustibility of the first fuel F1 can be made higher than that of the second fuel F2 depending on the mixture ratio of hydrogen and natural gas. Therefore, by employing the configuration of this embodiment, it is possible to realize a configuration of the combustor 3 that is suitable for both the first fuel F1 and the second fuel F2. Furthermore, by adjusting the fuel compositions of the first fuel F1 and the second fuel F2 in this way, flame stability can be ensured while reducing the occurrence of flashback.

In the embodiment, the second fuel F2 is injected more upstream of the mixing pipe 30 than the first fuel F1, but the present invention is not limited to this. The configuration may be such that the first fuel F1 is injected more upstream of the mixing tube 30 than the second fuel F2, or the first fuel F1 and the second fuel F2 are injected at the same position in the direction of the central axis O2. It's okay.

[Additional notes]
The combustor 3 and gas turbine 1 described in each embodiment are understood as follows, for example.

(1) The combustor 3 according to the first aspect includes a mixing pipe 30 that extends through an upstream end surface 21 and a downstream end surface 22 that are perpendicular to the combustor axis O1, and into which air A is introduced from the upstream end surface 21 side. a first fuel injection part 40 capable of injecting the first fuel F1 along the central axis O2 of the mixing tube 30 inside the mixing tube 30, and the central axis O2 of the mixing tube 30. The combustor 3 includes a second fuel injection part 70 that can inject the second fuel F2 into the mixing pipe 30 on the outside in the radial direction of O2.

Since the first fuel injection part 40 injects fuel along the central axis O2 of the mixing tube 30, it is possible to suppress an increase in the fuel concentration of the first fuel F1 on the wall surface of the mixing tube 30. On the other hand, since the second fuel F2 is injected from the second fuel injection part 70 at a position away from the center axis O2 of the mixing tube 30, an extreme drop in the fuel concentration near the wall surface of the mixing tube 30 can be avoided. .
This makes it possible to perform stable combustion while suppressing flashback.

(2) The combustor 3 according to the second aspect is the combustor 3 according to the first aspect, in which the first fuel injection section 40 is arranged in the mixing pipe 30 more than the second fuel injection section 70. The first fuel F1 may be injected on the downstream side.

The second fuel F2 is injected by the second fuel injection unit 70 at a position away from the center axis O2 of the mixing tube 30, thereby spreading and spreading the second fuel F2 over the entire area in the cross section of the flow path of the mixing tube 30. be able to. The first fuel injection part 40, in which the first fuel F1 is injected along the central axis O2 of the mixing tube 30, is located downstream of the second fuel injection part 70, so that the first fuel F1 is injected. The path from the point to the outlet of the mixing tube 30 is short. Therefore, it is possible to prevent the first fuel F1 from diffusing and reaching the inner wall surface 33 of the mixing tube 30.

(3) The combustor 3 according to the third aspect is the combustor 3 according to the first aspect or the second aspect, in which the second fuel injection part 70 is connected to the inner wall surface of the mixing pipe 30. 33 into the mixing tube 30 may have a wall hole 71 through which the second fuel F2 can be injected.

By injecting the second fuel F2 from the inner wall surface 33 of the mixing tube 30 by the second fuel injection part 70, the fuel concentration on the inner wall surface 33 at the outlet of the mixing tube 30 can be increased. This increases the combustion speed at the starting point of flame stabilization, making it possible to stabilize the flame.

(4) The combustor 3 according to the fourth aspect is the combustor 3 according to any one of the first to third aspects, and the first fuel injection section 40 is connected to the mixing pipe. 30, a fuel nozzle 41 extending in the direction of the central axis O2 and having a tip opening 45 formed at the downstream end for injecting the first fuel F1; A strut 50 extends in the radial direction of the center axis O2 between the fuel nozzle 41 and the inner wall surface 33 of the mixing pipe 30, and connects the fuel nozzle to the fuel nozzle via the inside of the strut 50. 41 may include a fuel introduction path for introducing the first fuel F1.

Thereby, the first fuel F1 can be appropriately injected by the first fuel injection unit 40 along the central axis O2 of the mixing tube 30.

(5) The combustor 3 according to the fifth aspect is the combustor 3 according to the fourth aspect, in which the strut 50 has an upstream end as a leading edge 51 and a downstream end. It may have an airfoil shape with a trailing edge 52.

Thereby, the air A in the mixing tube 30 can be smoothly circulated, and an increase in pressure loss can be suppressed.

(6) The combustor 3 according to the sixth aspect is the combustor 3 according to the fourth aspect or the fifth aspect, in which the inner wall surface 33 of the mixing pipe 30 is connected to the upstream end surface 21. an upstream wall surface 33a extending downstream with a uniform inner diameter; a decreasing diameter wall surface 33b connected to the downstream side of the upstream wall surface 33a and decreasing in diameter toward the downstream side; The downstream wall surface 33c may be connected to the downstream side and have a smaller diameter than the upstream wall surface 33a and reach the downstream end surface 22 with a uniform inner diameter.

A part of the mixing tube 30 has a diameter-reduced wall surface 33b, and by forming a constricted flow path, the flow velocity within the mixing tube 30 can be increased. Thereby, it is possible to avoid flame holding at an unintended location within the mixing tube 30.

(7) The combustor 3 according to the seventh aspect is the combustor 3 according to the sixth aspect, in which the diameter-reducing wall surface 33b is located at the position of the upstream end of the strut 50 in the central axis O2 direction. It may extend from the tip opening 45 to a position in the direction of the central axis O2.

By narrowing the flow path of the mixing tube 30 in accordance with the arrangement position of the strut 50, it is possible to avoid the occurrence of a low speed region within the mixing tube 30. Thereby, unintended flame holding within the mixing tube 30 can be further avoided.

(8) The combustor 3 according to the eighth aspect is the combustor 3 according to any one of the fourth to seventh aspects, and the second fuel injection section 70 is connected to the strut 50. It may have a surface hole 72 through which the second fuel F2 can be injected into the mixing tube 30 from the surface thereof.

This also allows the second fuel F2 to be injected at a position away from the central axis O2 of the mixing tube 30, so that the fuel concentration on the inner wall surface 33 at the outlet of the mixing tube 30 can be increased. This increases the combustion speed at the starting point of flame stabilization, making it possible to stabilize the flame.

(9) The combustor 3 according to the ninth aspect is the combustor 3 according to any one of the first to eighth aspects, in which the first fuel F1 is the second fuel F2. It may be said that it is a more flammable component.

When using the easily flammable first fuel F1, by injecting it along the central axis O2 of the mixing tube 30, it is possible to suppress the first fuel F1 from reaching the inner wall surface 33 of the mixing tube 30. Thereby, it is possible to suppress an increase in fuel concentration near the inner wall surface 33 of the mixing tube 30, and to suppress the occurrence of flashback.
On the other hand, when using the second fuel F2 that is difficult to burn, by injecting it from the inner wall surface 33 of the mixing tube 30, the fuel concentration near the inner wall surface 33 can be increased. This increases the combustion speed at the starting point of flame holding at the outlet of the mixing tube 30, making it possible to perform stable flame holding.

(10) The gas turbine 1 according to the tenth aspect has a compressor 2 that generates air A, and a premixed gas M that is generated by mixing fuel with the air A compressed by the compressor 2. The combustor 3 includes a combustor 3 of any one of the first to ninth modes that generates gas C, and a turbine 4 that is driven by the combustion gas C.

According to the present disclosure, it is possible to provide a combustor and a gas turbine that can avoid misfire while suppressing flashback.

1 Gas turbine 2 Compressor 3 Combustor 4 Turbine 10 Outer cylinder 11 End cover 15 Inner cylinder 17 Support part 20 Combustor plate 21 Upstream end face 22 Downstream end face 30 Mixing tube 31 Inlet opening 32 Outlet opening 33 Inner wall surface 33a Upstream wall surface 33b Reduction Diameter wall surface 33c Downstream wall surface 35 First plenum 36 Second plenum 37 Connection member 38 First fuel supply system 39 Second fuel supply system 40 First fuel injection section 41 Fuel nozzle 42 Cavity 45 Tip opening 50 Strut 51 Leading edge 52 Trailing edge 53 Wing surface 60 Fuel introduction part 70 Second fuel injection part 71 Wall hole 72 Surface hole A Air M Premixed gas C Combustion gas O1 Combustor axis O2 Center axis F1 First fuel F2 Second fuel

Claims

a combustor plate having a mixing tube extending through an upstream end face and a downstream end face perpendicular to the combustor axis and into which air is introduced from the upstream end face side;
a first fuel injection part capable of injecting a first fuel along the central axis of the mixing tube inside the mixing tube;
a second fuel injection part capable of injecting a second fuel into the mixing tube at a radially outer side of the central axis of the mixing tube;
A combustor equipped with a
The combustor according to claim 1, wherein the first fuel injection section injects the first fuel on the downstream side of the mixing tube rather than the second fuel injection section.
The second fuel injection section is
The combustor according to claim 1 or 2, further comprising a wall hole through which the second fuel can be injected into the mixing tube from the inner wall surface of the mixing tube.
The first fuel injection section is
a fuel nozzle extending in the central axis direction inside the mixing tube and having a tip opening formed at the downstream end for injecting the first fuel;
a strut that extends in a radial direction of the central axis between the fuel nozzle and the inner wall surface of the mixing tube and connects the fuel nozzle and the inner wall surface of the mixing tube;
a fuel introduction path for introducing the first fuel into the fuel nozzle via the inside of the strut;
The combustor according to claim 1 or 2, comprising:
The combustor according to claim 4, wherein the strut has an airfoil shape with an upstream end serving as a leading edge and a downstream end serving as a trailing edge.
The inner wall surface of the mixing tube is
an upstream wall surface connected to the upstream end surface and extending toward the downstream side with a uniform inner diameter;
a diameter-reducing wall surface connected to the downstream side of the upstream wall surface and decreasing in diameter toward the downstream side;
a downstream wall surface that is connected to the downstream side of the reduced diameter wall surface, has a smaller diameter than the upstream wall surface, and has a uniform inner diameter and reaches the downstream end surface;
The combustor according to claim 4, having:
The combustor according to claim 6, wherein the reduced diameter wall surface extends from the upstream end of the strut in the central axial direction to the tip opening in the central axial direction.
The second fuel injection section is
The combustor according to claim 4, further comprising surface holes through which a second fuel can be injected into the mixing tube from the surface of the strut.
The combustor according to claim 1 or 2, wherein the first fuel has a more combustible component than the second fuel.
a compressor that generates air;
The combustor according to claim 1 or 2, which generates combustion gas by combusting a premixed gas generated by mixing fuel with air compressed by a compressor;
a turbine driven by the combustion gas;
A gas turbine equipped with